we really should be able to use our weapons in the water, at the very least certain weapons. Knives and spears should be able to be used with no hindrance. It'd certainly give a reason to use spears. But, this is also predicated on them buffing/bringing more depth to swimming, which they probably won't. If swimming is fully intended to put the player at a complete handicap then there really shouldn't be a skill for it in the first place.